As a kind of short-range wireless communications, wireless communications by NFC (Near Field Communication) using 13.56 MHz as a carrier frequency are available. Meanwhile, also proposed is a technique of performing non-contact power supply by a magnetic field resonance method with use of coils that are used for NFC communications.
For the non-contact power supply with use of magnetic field resonance, a power transmission-side resonant circuit including a power transmission-side coil is placed in a power supply device while a power reception-side resonant circuit including a power reception-side coil is placed in an electronic device as a power reception device, where resonance frequencies of those resonant circuits are set to a common reference frequency. With this arrangement, an AC current is passed through the power transmission-side coil so that an alternating magnetic field of the reference frequency is generated in the power transmission-side coil. Then, the alternating magnetic field is transferred to the power reception-side resonant circuit that resonates at the reference frequency, causing an AC current to flow through the power reception-side coil. That is, electric power is transferred from the power transmission-side resonant circuit including the power transmission-side coil to the power reception-side resonant circuit including the power reception-side coil.